
    <!DOCTYPE html>
    <html lang="zh-CN">
    <head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <title>RabbitMQ死信和延时队列 - 交互式测验</title>
      <style>
        @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700&display=swap');
        
        body {
          font-family: 'Noto Sans SC', sans-serif;
          background-color: #f4f7f9;
          color: #333;
          display: flex;
          justify-content: center;
          align-items: center;
          min-height: 100vh;
          margin: 0;
          padding: 20px;
          box-sizing: border-box;
        }
        
        .main-wrapper {
            position: relative;
            width: 100%;
            max-width: 900px; /* Wider to accommodate buttons */
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .quiz-container {
          background-color: #ffffff;
          border-radius: 16px;
          box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
          width: 100%;
          max-width: 700px;
          overflow: hidden;
          z-index: 10;
        }

        .quiz-header {
          background-color: #4a90e2;
          color: white;
          padding: 20px 30px;
          text-align: center;
        }

        .quiz-header h1 {
          margin: 0;
          font-size: 24px;
          font-weight: 700;
        }
        
        .quiz-header p {
            margin: 5px 0 0;
            font-size: 14px;
            opacity: 0.9;
        }

        .quiz-body {
          padding: 30px;
        }

        .progress-bar {
            display: none; /* 隐藏进度条 */
            width: 100%;
            background-color: #e0e0e0;
            border-radius: 5px;
            height: 10px;
            margin-bottom: 20px;
        }

        #progress-indicator {
            height: 100%;
            width: 0%;
            background-color: #4caf50;
            border-radius: 5px;
            transition: width 0.3s ease;
        }

        #question-container {
          margin-bottom: 20px;
        }

        #question-text {
          font-size: 18px;
          font-weight: 500;
          line-height: 1.6;
          margin-bottom: 25px;
        }

        .options-list {
          list-style: none;
          padding: 0;
          margin: 0;
        }

        .option-item {
          background-color: #f8f9fa;
          border: 1px solid #dee2e6;
          border-radius: 8px;
          padding: 15px;
          margin-bottom: 12px;
          cursor: pointer;
          transition: background-color 0.2s ease, border-color 0.2s ease;
        }

        .option-item:hover {
          background-color: #e9ecef;
        }
        
        .option-item.selected {
            background-color: #d1e7fd;
            border-color: #4a90e2;
        }

        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }
        
        #next-btn {
            background-color: #28a745;
        }

        .nav-btn:hover {
          background-color: #357abd;
          transform: scale(1.05);
        }
        
        .nav-btn:disabled {
            background-color: #a0c3e8;
            cursor: not-allowed;
            opacity: 0.7;
        }

        #result-container {
            border-top: 1px solid #eee;
        }
        
        .result-box {
            border-radius: 8px;
            padding: 20px;
            margin-top: 20px;
        }
        
        .result-box.correct {
            background-color: #d4edda;
            border: 1px solid #c3e6cb;
            color: #155724;
        }

        .result-box.incorrect {
            background-color: #f8d7da;
            border: 1px solid #f5c6cb;
            color: #721c24;
        }
        
        .result-box h3 {
            margin-top: 0;
        }

        .explanation-text {
            margin-top: 15px;
            line-height: 1.7;
        }
        
        .source-text {
            font-style: italic;
            font-size: 14px;
            margin-top: 15px;
            color: #555;
        }

        
        .final-score-container {
            padding: 40px;
            text-align: center;
        }
        .final-score-container h2 {
            margin-top: 0;
            margin-bottom: 30px;
        }
        .score-summary {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }
        .score-card {
            background-color: #f8f9fa;
            border-radius: 12px;
            padding: 20px;
            width: 180px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
        }
        .score-card h3 {
            margin: 0 0 10px;
            font-size: 16px;
            font-weight: 500;
            color: #555;
        }
        .score-card p {
            margin: 0;
            font-size: 28px;
            font-weight: 700;
            color: #333;
        }
        .score-details table {
            width: 100%;
            font-size: 16px;
        }
        .score-details td {
            padding: 4px 0;
        }
        .score-details td:last-child {
            text-align: right;
            font-weight: 700;
        }
        .report-actions button {
            background-color: #fff;
            border: 1px solid #ccc;
            border-radius: 8px;
            padding: 12px 25px;
            font-size: 16px;
            cursor: pointer;
            margin: 0 10px;
            transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
        }
        .report-actions button:hover {
            background-color: #f1f1f1;
            border-color: #bbb;
            transform: translateY(-2px);
        }
        .report-actions button.primary {
            background-color: #28a745;
            color: white;
            border-color: #28a745;
        }
        .report-actions button.primary:hover {
            background-color: #218838;
        }
        
        .hint-container {
            background-color: #e0f7fa;
            border: 1px solid #b2ebf2;
            border-radius: 8px;
            padding: 15px;
            margin-top: 20px;
            color: #006064;
            font-size: 15px;
            line-height: 1.6;
            display: none; /* 默认隐藏 */
        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>RabbitMQ死信和延时队列 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "根据文档描述，以下哪种情况会导致消息进入死信队列？",
    "options": [
      "消费者调用 basic.reject 或 basic.nack 拒绝消息，并且设置 requeue=true。",
      "消费者在处理消息时发生网络中断，导致与MQ的连接断开。",
      "消息被消费者拒绝（通过 basic.reject 或 basic.nack），并且参数 requeue 设置为 false。",
      "生产者发送消息时，指定的交换机不存在。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档明确指出了消息成为“死信”的三个来源之一是：消息被拒绝（basic.reject或basic.nack）并且requeue=false。当 requeue=true 时，消息会重新回到原队列头部等待再次消费，而不是进入死信队列。消费者网络中断会导致消息重新变为待分配状态，而交换机不存在会导致生产者发送失败（可能触发return机制），这些都不会直接让消息进入死信队列。",
    "source": "文档中「死信队列的来源」部分",
    "hint": "文档中列举了三种消息会成为“死信”的来源，其中一种与消费者拒绝消息时的特定参数设置有关。"
  },
  {
    "question": "在 RabbitMQ 中实现延迟队列，通常利用了哪些核心机制的组合？",
    "options": [
      "消息持久化机制和消费者优先级",
      "消息的TTL（Time-To-Live）机制和死信队列（DLQ）",
      "事务消息机制和ConfirmCallback",
      "推（Push）模式和拉（Pull）模式的切换"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档解释道，延迟队列的实现依赖于RabbitMQ的TTL机制。当为某个队列或消息设置了存活时间（TTL）后，如果消息在规定时间内未被消费，它就会过期变成“死信”，然后被路由到预先配置好的死信队列中。消费者监听这个死信队列，就实现了延迟消费的效果。",
    "source": "文档中「延时队列的设置」部分",
    "hint": "思考一下，当一条消息“过期”后会变成什么？这种变化是如何被我们用来实现延迟效果的？"
  },
  {
    "question": "在配置业务队列使其具备死信功能时，需要在队列的参数（arguments）中设置哪两个关键属性？",
    "options": [
      "x-dead-letter-exchange 和 x-dead-letter-routing-key",
      "x-message-ttl 和 x-expires",
      "x-max-length 和 x-overflow",
      "x-alternate-exchange 和 x-message-priority"
    ],
    "correctAnswerIndex": 0,
    "explanation": "根据文档中的Java配置示例，为了给一个业务队列指定其死信的去向，需要设置 `x-dead-letter-exchange` 来声明当前队列绑定的死信交换机，以及 `x-dead-letter-routing-key` 来声明死信消息被转发到死信交换机时所使用的路由键。",
    "source": "文档中「配置死信队列」部分的Java代码示例",
    "hint": "在配置业务队列的Bean定义中，有两个以 'x-dead-letter-' 开头的参数是关键。"
  },
  {
    "question": "当消费者使用 `channel.basicNack(deliveryTag, false, false)` 方法来拒绝一条消息时，会发生什么？",
    "options": [
      "消息被重新放回原队列的头部，等待下一次投递。",
      "消息被重新放回原队列的尾部。",
      "消息被丢弃，如果配置了死信队列，它将被发送到死信队列。",
      "消息会一直处于“待应答(unacked)”状态，直到消费者重启。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`basicNack` 方法的第三个参数是 `requeue`。当 `requeue` 设置为 `false` 时，表示不将该消息重新入队。此时，如果该队列绑定了死信交换机，这条被拒绝的消息就会成为死信并被路由到死信队列；如果没有配置，消息则会被丢弃。",
    "source": "文档中「设置消费者」及「参数说明」部分",
    "hint": "`basicNack` 方法的第三个布尔参数 `requeue` 决定了被拒绝消息的命运。"
  },
  {
    "question": "文档提到了设置消息TTL的两种方式：为整个队列设置TTL和为单条消息设置TTL。这两种方式在消息过期处理上有什么主要区别？",
    "options": [
      "为队列设置TTL的性能远低于为单条消息设置TTL。",
      "为队列设置TTL，消息一旦过期就会被丢弃；而为单条消息设置TTL，即使消息过期也可能因为队列积压而存活较长时间。",
      "两者没有本质区别，RabbitMQ会统一处理。",
      "为单条消息设置的TTL会覆盖队列的TTL设置，但处理机制完全相同。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档中特别强调了这两种方式的区别：“如果设置了队列的TTL属性，那么一旦消息过期，就会被队列丢弃...而第二种方式（为单条消息设置TTL），消息即使过期，也不一定会被马上丢弃，因为消息是否过期是在即将投递到消费者之前判定的”。这是因为检查整个队列中不同过期时间的消息成本很高。",
    "source": "文档中「延时队列的设置」部分的说明引用块",
    "hint": "文档中有一段粗体文字解释了这两种方式处理过期的时机差异，尤其是在队列有积压的情况下。"
  },
  {
    "question": "在消费者消息确认机制中，将 `autoAck` 参数设置为 `true` (自动ACK) 可能带来什么风险？",
    "options": [
      "消费者处理消息的性能会大幅下降。",
      "如果消费者在处理完消息逻辑前异常退出，该消息会丢失。",
      "RabbitMQ服务器的CPU和内存消耗会显著增加。",
      "会导致消息在队列中无限期积压，无法被消费。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档指出，当 `autoAck` 为 `true` 时，RabbitMQ在把消息发送给消费者后会立即将其标记为已确认并删除，而不管消费者是否真正成功处理了消息。如果消费者进程在处理业务逻辑时崩溃，这条消息就永久丢失了，因为它已经被MQ移除了。因此，为了保证消息的可靠处理，通常推荐使用手动ACK。",
    "source": "文档中「自动ACK」部分",
    "hint": "自动ACK模式下，MQ何时认为消息被成功消费了？如果在这个时间点之后、消费者业务处理完成之前发生故障，会发生什么？"
  },
  {
    "question": "一条消息成为“死信”后，它的路由键（routing key）会如何变化？",
    "options": [
      "它的路由键总是会被清空。",
      "如果原队列配置了 `x-dead-letter-routing-key`，则路由键被替换为该值；否则保留原有路由键。",
      "它的路由键总是会被替换为队列的名称。",
      "路由键保持不变，但会额外增加一个表示“死信”的头信息。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确说明了死信消息路由键的变化规则：如果在原队列上通过 `x-dead-letter-routing-key` 参数指定了新的路由键，那么死信的路由键就会被替换成这个新值。如果没有进行此项配置，那么死信消息将保留其进入业务队列时的原始路由键。",
    "source": "文档中「死信消息的变化」部分",
    "hint": "这个问题的关键在于业务队列的一个可选配置参数，它能决定死信消息被转发时的路由规则。"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
          }

          updateProgress();

          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
        }
        
        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
        }
        
        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  